In the past, there has been known a technique for transmitting and receiving data through a network. For example, there has been known a storage system where data is transferred from one transmission source device to a plurality of end hosts, end hosts duplicate the received data, and hence, the reliability of data or read-write performance is improved.
FIG. 22 is a diagram illustrating an example of a storage system of the related art. In the example illustrated in FIG. 22, a storage system 70 includes a transmission source server 71, a plurality of network switches 72 and 73, and a plurality of end hosts 74 to 76. In addition, the network switch 72 is connected to the transmission source server 71, the end host 74, and the network switch 73. In addition, the network switch 73 is connected to the network switch 72, the end host 75, and the end host 76.
Here, in order to duplicate data in the individual end hosts 74 to 76, the transmission source server 71 performs the transmission of data using multi-unicast or a chain. For example, in the storage system 70, when data is transferred using the multi-unicast, data paths used for unicast are individually generated with respect to the individual end hosts 74 to 76, and data is transmitted through the individual data paths.
In detail, the transmission source server 71 generates a data path for transmitting data to the end host 74 through the network switch 72. In addition, the transmission source server 71 individually generates data paths for transmitting data to the end host 75 and the end host 76 through the network switch 72 and the network switch 73. In addition, the transmission source server 71 transfers data through the individual generated data paths.
In addition, for example, when transferring data using the chain, the transmission source server 71 transmits the data to the end host 74 through the network switch 72. Then, the end host 74 duplicates and stores therein the data, and transmits the data to the end host 75 through the network switches 72 and 73.
Upon receiving the data from the end host 74, the end host 75 duplicates and stores therein the data, and transmits the data to the end host 76 through the network switch 73. In this way, in the storage system 70, data is transferred from the transmission source server 71 to the individual end hosts 74 to 76, along a chain-like route tracking all the end hosts 74 to 76.
Here, there has been known the technique of multicast where, in order to realize efficient data transfer, data is simultaneously transferred to a specific group of transmission destination devices selected from among transmission destination devices connected to a network.
For example, when the storage system 70 transmits data using the technique of multicast, an internet group management protocol (IGMP) report is transmitted from an end host participating in a group of end hosts serving as transmission destinations of the data. Here, upon receiving the IGMP report, each of the network switches 72 and 73 registers, in a multicast table, a multicast address indicating a group serving as a transmission destination of the data, in association with information on a port having received the IGMP report.
In addition, upon receiving data to which a multicast address is assigned, each of the network switches 72 and 73 refers to the multicast table, and identifies a port associated with the multicast address assigned to the data. Thereafter, each of the network switches 72 and 73 sends out data from the identified port.
A technique of the related art has been disclosed in Japanese Laid-open Patent Publication No. 2000-004251.
A technique of the related art has also been disclosed in M. Christensen, K. Kimball, and F. Solensky, Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Snooping Switches (RFC 4541), May 2006, or B. Cain, S. Deering, I. Kouvelas, B. Fenner, and A. Thyagarajan, Internet Management Group Protocol, Version 3 (RFC 3376), October 2002.